%% Copyright (c) 2013-2014 Cloudozer LLP. All rights reserved.
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%% * Redistributions in any form must be accompanied by information on how to
%% obtain complete source code for the LING software and any accompanying
%% software that uses the LING software. The source code must either be included
%% in the distribution or be available for no more than the cost of distribution
%% plus a nominal fee, and must be freely redistributable under reasonable
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%% code for all modules it contains. It does not include source code for modules
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%%
%% @doc interface module to disk_server.
%%
-module(disk).

-export([read/2,write/2]).
-export([barrier/0,flush/0]).

-define(SERVER, disk_server).

%% @doc Read sectors from the disk.
-spec read(integer(), integer()) -> {ok,binary} | {error,_}.

read(Start, NumSect) when is_integer(Start), is_integer(NumSect) ->
	gen_server:call(?SERVER, {read,Start,NumSect});
read(_, _) ->
	{error,badarg}.

%% @doc Write sectors to the disk.
-spec write(integer(), binary()) -> ok | {error,_}.

write(Start, Data) when is_integer(Start), is_binary(Data) ->
	gen_server:call(?SERVER, {write,Start,Data});
write(_, _) ->
	{error,badarg}.

%% @doc Prevent reordering of write operations.
-spec barrier() -> ok | {error,_}.

barrier() ->
	gen_server:call(?SERVER, barrier).

%% @doc Flush the disk cache.
-spec flush() -> ok | {error,_}.

flush() ->
	gen_server:call(?SERVER, flush).

%%EOF
